There were 22 legs creeping across the web. How many flies? How many spiders?

Eggs in Baskets

Stage: 1 Challenge Level:

We had over two hundred solutions to this
problem! I'm just sorry that we can't mention you all.

There seemed to be two different ways that you
used to solve it. Some of you tried out numbers in a logical way
until you found the ones that worked, like Erika from East Bergholt
High School who wrote:

If there was 1 egg in the brown basket, no eggs in the red
basket and 3 eggs in the pink basket, that would only make 4
eggs.
If there were 2 eggs in the brown basket, 1 egg in the red basket
and 4 eggs in the pink basket, this only makes 7 eggs.
So finally, if there were 3 eggs in the brown basket, 2 eggs in the
red basket and 5 eggs in the pink basket, there would be 10 eggs
altogether.

Absolutely correct - thank you Erika.

Phoebe, Alice and Luke from Cambridge also did
the problem in this kind of way, but they used counters to help
them. Their Dad explained how they went about finding the
solution:

Each had a piece of A4 paper and a pencil which was coloured
either red, brown or pink. They drew a basket on their paper in the
colour they had been given. They had 10 counters between them to
represent the eggs. Phoebe read out the conditions and they started
with 4 counters in the red basket, 4 in the brown and 2 in the
pink. However, they knew this didn't satisfy the first condition
(that the brown basket had to have one more egg than the red) so
Alice moved one counter from the red basket to the brown basket.
But they soon realised that now there were 5 in the brown and only
3 in the red, so still the first condition wasn't satisfied. The
three of them talked about it more and took one counter out of the
brown basket, so now there were 4 in the brown and 3 in each of the
red and the pink. However, this didn't satisfy the second condition
(that the red has three less than the pink). After playing around
with the counters a bit more, they eventually found the solution -
the red basket has 2 eggs, the brown basket has 3 eggs and the pink
has 5.

Well done! It can be a very good idea to use
some sort of "equipment" to help answer problems.

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embed rich mathematical tasks into everyday classroom practice. More information on many of our other activities
can be found here.